A man walks for 5 hours... he walks on a flat road at 4km/hr then goes up a hill at 3km/hr and turns around and walks down at 6km/h.
How far did he travel?
2006-09-05 18:05:19 · 10 answers · asked by WhiteHat 6 in Science & Mathematics ➔ Mathematics
Since it is linear there is an answer.
We want 4x+3y+6z
Given x+y+z=5
We are also given 3y=6x (assuming he stops at the bottom of the hill which is how I interpreted it).
That gives us y=2z
Plug that into x+y+z=5 gives us
x+2z+z=5+>z=(5-x)/3
We start off assuming x can go from 0 to 5 meaning zcan go from 0 to 5/3. This implies y goes from 0 to 10/3.
Since this is a linear combination there will be maximums and minimums only at the endpoints. Plug in x=0, z=5/3, y=10/3 results in 20. Plug in x=5, z=0, y=0 results in 20.
It's a flat combination all resulting in 20.
2006-09-05 18:22:27 · answer #1 · answered by managuense 1 · 1⤊ 2⤋
It's a trick question, because it looks as though there isn't enough information for the answer. But from the exact way the numbers have been chosen, there is only one answer after all.
For each km of hill, it takes him 20 minutes to go up, and 10 minutes to come down. That makes 2 km in 30 minutes, or 4 km per hour, the same as on the flat. So the answer is 20 km, no matter what size the hill is.
The question doesn't actually say that the man walked all the way back down the hill that he went up, so you could get any answer from 15 km to 20 km, but that's not mathematics.
2006-09-06 00:27:12 · answer #2 · answered by bh8153 7 · 0⤊ 0⤋
As others have said, there isn't enough information. For example:
Assume that he walked 1 hour at 4km/hr, 1 hr at 3km/hr and 3 hours at 6 km/hr. Then he would have walked 25 km.
Suppose then that he walked 1 hr at 4 km/hr, 3 hrs at 3 km/hr, and 1 hr at 6 km/hr. Then he would have walked 19 km.
Since there are two possible answers, then actually, there are infinite possible answers. This imples taht there is not enough info provided to answer the question.
2006-09-05 18:15:38 · answer #3 · answered by a_liberal_economist 3 · 0⤊ 0⤋
I think there is some information missing in the problem. The problem is that you have no idea how long the flat road or the hill are. You also don't know if he came all the way down the hill, came back to his starting point, etc. You need some more information so that the distance can be determined.
2006-09-05 18:10:33 · answer #4 · answered by phosphoricx3 2 · 0⤊ 0⤋
It has more than one answers,
1. 0.3hour on flat road = 1.2 Km then 2.93 hours to went up a hill =8.79 km , 1.465 hour took came down of the hill = 8.79km and 0.3 more hour he traveled on the flat road to reach origin = 1.2km. So total km covered is 19.98 km.
2. 0.5 hour on flat road = 2 Km then 2.66 hours to went up a hill =7.98 km , 1 hour he spent on the top of hill,1.33 hour took came down of the hill = 7.98km and 0.5 hour more he traveled on the flat road to reach origin = 2km. So total km covered is 19.96km.
I think your question is a funny one. But i don't repent about wasting my valuable time on your question.
2006-09-05 20:46:17 · answer #5 · answered by jintocd 1 · 0⤊ 0⤋
There's not enough information there to get an answer.
2006-09-05 18:09:24 · answer #6 · answered by Demiurge42 7 · 0⤊ 0⤋
I hated these questions in school.....why didn't he just take the bus? Or ride his bike? LOL
2006-09-05 18:10:51 · answer #7 · answered by basketcase88 7 · 0⤊ 0⤋
there isn't much information about this question
2006-09-05 18:11:43 · answer #8 · answered by xLostLoLx 2 · 0⤊ 0⤋
i think its 20km im not positive though
2006-09-05 18:09:39 · answer #9 · answered by newyorktocountry 2 · 0⤊ 0⤋
13km
2006-09-05 18:25:47 · answer #10 · answered by Anonymous · 0⤊ 0⤋